Pivot and bearing assembly



Sept. 23, 1952 H. A. HADLEY 2,611,652

PIVOT mo BEARING ASSEMBLY Filed lay 4, 1949 mmvron.

HARLAN A. HADLEY ATTORNEY Patented Sept. 23, 1952 PIVOT AND BEARING ASSEMBLY Harlan A. Hadley, Burlington, Vt., assignor to H. A. Hadley Associates, Inc., Burlington, Vt., a corporation of Vermont Application May 4, 1949, Serial No. 91,266

18 Claims.

This invention relates to weighing scales, and relates more particularly to a knife edge pivot and bearing assembly adapted for use in weighing scales.

This invention is a modification of the invention disclosed in my application Serial No. 73,270, filed January 28, 1949.

In many weighing mechanisms, levers are supported and the forces are transmitted to and from the levers by means of knife edge pivot and bearing assemblies in which the knife edge pivot rests in a suitably mounted bearing provided with a V-groove. The V-groove normally positions the pivot in a longitudinal plane and anti-friction plates applied to the end of the bearing block normally restrain the pivot from endwise motion. As is well known, such pivot and bearing assemblies are not wholly satisfactory since their use leads to inaccuracies in weighing. Thus, since the V-groove must be made with a bottom having a slight radius to prevent frictional contact of the sides of the V-groove with the sides of the knife edge pivot, the knife edge pivot skates" over the surface of the flattened bottom of the V-groove causing the lever to assume readily a different position for every different position of the knife edge pivot on the radius portion of the V-groove. The movement of the pivot relative to the radius portion of the V-groov alters the pivot distances, resulting in inaccuracies in the weighing.

It is an important object of this invention to provide an improved knife edge pivot and bearing assembly which will be fre from the abovementioned and other disadvantages and which will be especially simple in construction and emcient in use.

Another object of this invention is to provide a knif edge pivot and bearing assembly wherein the knife edge pivot cooperates with a flat bearing surface and wherein the pivot and the bearing are connected to each other to maintain the same in predetermined operative position relative to each other so that the pivot is fre to turn on its normal axis but is restrained from movement in any other direction.

A further object of this invention is to provide a. novel means for holding the pivot and bearing in predetermined operative relation to each other.

Still another object of this invention is the provision of a novel flexibl member for holding the pivot and bearing in predetermined operative relation to each other.

Other objects of this invention, together with certain details of construction and combinations of parts, will be apparent from the following description and will be pointed out in the appended claims.

In the drawing, wherein a preferred embodiment of my invention is shown,

Fig. 1 is a perspective view of my novel knife edge pivot and bearing assembly, and

Fig. 2 is a perspective view of one corner of a platform scale showing the knife edge pivot and bearing assemblies of my invention in operative position in said platform scale.

Like reference numerals indicate like parts throughout both views of the drawing.

Referring now to the drawing for a detailed description of my invention, the reference numeral 3 indicates generally a knife edge pivot and bearing assembly of my invention. The assembly comprises a bearing block 4 made of any suitable material of sufficient hardness. Preferably, the bearing block is made of Norbide, a compound of boron and carbon, the bearing surface 5 of which is ground to optical flatness.

The knife edge pivot 6 of the assembly is preferably made of Carb'oloy, a tungsten-carbon alloy. but may also be made of steel or any other suitable material. The knife edge pivot B is maintained in proper position on the flat surface of the bearing 4 by means of a flexible block Tencasing substantially the Whole of said pivot. The flexible block 1 may be made of suitable material, preferably an elastomer such as natural or synthetic rubber. The block of elastomer is molded about and bonded to the knife edge pivot 6 with only the knife edge 8 thereof in free contact with the surface 5 of the bearing block 4, or the pivot may be inserted in said block 1 after it is molded or shaped to the form desired. The rubber block 1 is suitably bonded or welded to the surface 5 of the bearing block 4. In this manner, th knife edge is substantially fixed in position so that skating" of the same over the surface of the bearing block is prevented. Accordingly, inaccuracies in weighing are avoided.

In Fig. 2, two knife edge pivot and bearing assemblies are shown operatively applied to a scale structure. Thus, one assembly is supported on fulcrum stand 9 and the knife edge pivot of this assembly functions as the fulcrum pivot. For attachment to the scale lever II, the pivot 6 is provided with an integral shank l2 of reduced, and preferably round, cross-section, which is adapted to be fixed to the scale lever l I by a force fit in an opening therein, or in any other suitable manner. The other knife edge pivot and bearing assembly shown in Fig. 2 is similarly attached to lever II by means of shank i2, the knife edge pivot of this assembly functioning as the load pivot. The block 4 of the latter assembly having thereon a girder chain III for supporting the platform it of thescale.

While the knife edge pivot and bearing assembly of my invention has been shown and described in connection with a platform scale, it is to be understood that the said assembly may be employed wherever knife edge pivots and bearings of this type are normally employed in weighing scales.

The embodiment of my invention shown and described herein is to be considered merely as illustrative, as my invention is susceptible to variation, modification and change within the spirit and scope of the appended claims.

Iclaim:

l. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of resilient material in physical contact with said pivot and said bearing.

2. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing. and means for maintaining said knife edge in operative relation to said bearing. said means comprising a block of an elastomer in physical contact with said pivot and said bearing.

3. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of rubber in physical contact with said pivot and said bearing.

4. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means omprising a blOCk of resilient material fixed to said pivot and said bearing in physical contact with said pivot and said bearing.

5. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of an elastomer fixed to said pivot and said hearing.

6. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of rubber fixed to said pivot and said bearing.

7. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of resilient material bonded to the pivot and to the surface of said bearing.

8. A pivot and bearing assembly for weighing scalescomprising a bearing. a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing. said means comprising a block of an elastomer bonded to the pivot and to the surface of said bearing. J

9. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of rubber bonded to the pivot and to the surface of said bearing.

10. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of resilient material substantially surrounding said pivot and bonded to the surface of said bearing.

11. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing. said means comprising a block of an elastomer substantially surrounding said pivot and bonded to the surface of said bearing.

12. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of rubber substantially surrounding said pivot and bonded to the surface of said bearing.

13. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of resilient material molded about substantially the whole of said pivot and bonded to the surface of said bearing.

14. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of an elastomer molded about substantially the whole of said pivot and bonded to the surface of said bearing.

15. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of rubber molded about substantially the whole of said pivot and bonded to the surface of said bearing.

16. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of resilient material molded about substantially the whole of and bonded to said pivot and bonded to the surface of said bearing.

17. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of an elastomer molded about substantially the whole of and bonded to said pivot and bonded to the surface of said bearing.

18. A pivot and bearing assembly for weighing scales comprising a bearing, a pivot having a knife edge in contact with said bearing, and means for maintaining said knife edge in operative relation to said bearing, said means comprising a block of rubber molded about substantially the whole of and bonded to said pivot and bonded to the surface of said bearing.

HARLAN A. HADLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,071,761 Leake Sept. 2, 1913 1,290,564 Jankower Jan. 7, i919 

